Evaluation of techniques for lignocaine hydrochloride analgesia of velvet antler of adult stags by P. R. Wilson, K J Stafford, et.al., Massey University, Inst Vet Anim & Biomed Sci, Palmerston North, NEW ZEALAND, New Zealand Veterinary Journal, 2000, Vol. 48, Issue 6, pp 182-187
To evaluate the effectiveness of various routes of administration and doses of local anesthetic (LA) to provide analgesia of the velvet antler of adult stags.
In Experiment 1, antlers from 50 red deer stags, greater than or equal to 2-years-old were allocated to 1 of 4 treatment groups (n = 25 antlers/group) to receive injections with 2% lignocaine hydrochloride as follows: High-dose (1 ml/cm pedicle circumference) or Low-dose ring-block (0.4 ml/cm pedicle circumference) or, High- site or Low-site regional nerve block (5 mi per site, both of which included the auriculopalpebral nerve). An electrical stimulus was applied before application of LA and then each minute for up to 4 minutes after LA injection. If no response was observed, analgesia was tested with a saw cut. If no response occurred, the antler was cut at that time. If the animal responded, a further wait time was applied until 4 minute had elapsed, at which time observations ceased.
In Experiment 2, 10 primary and 50 re-growth antlers were given a High-dose ring-block and tested with a saw cut after 1 minute (n = 30) or 2 minute (n = 30). If no response occurred, the antler was removed. If a response occurred, further 1-minute wait periods were applied.
In the High-dose ring-block and High-site nerve-block groups, 24/25 and 21/25 antlers were removed without response by 2 minutes, compared with 20/25 and 15/25 antlers in the Low-dose ring-block and Low-site nerve-block groups, respectively. The High-dose ring-block provided more effective analgesia after 3 minutes than the Low-dose ring-block, as assessed by the number of stags that did not respond to the electrical stimulus (p = 0.008), or subsequent antler removal (p = 0.050). The numbers of antlers removed without response after 1 or 2 minutes were greater using the High-site nerve-block than the Low-site nerve-block (p = 0.002 and p = 0.037, respectively). In all but the High-dose ring-block group, at least 1 stag required further LA after 4 minutes, before antler could be humanely removed.
In Experiment 2, stags reacted to a saw-cut test on 6/30 antlers, 1 minute after a High-dose ring-block, compared with 1/30 antlers after 2 minutes (p = 0.051).
The High-dose ring-block produced the most effective and rapid analgesia.
A High-dose ring-block with a 2-minute wait period should be the preferred method for achieving local analgesia for velvet antler removal.